Reform is long overdue for Germany’s archaic medical-education system, which puts undue pressure on students and contaminates the scientific literature.
Researchers should add their voices to the effort to stop attacks on health workers in war zones.
A tribute to the nineteenth-century polymath whose algebra lets you search the Internet.
US military research suggests that electrodes can compensate for damaged tissue.
There were other options, but super close-up shots on descent will provide science bonanza.
Fuelled by El Niño and land-management blunders, fires consume precious habitat.
Tech funders warm to start-ups that use microbes in manufacturing.
Chemists succeed at forecasting how complex molecules will assemble in 3D.
National science academies decry religious intolerance and government's perceived embrace of superstition.
A London lab is deploying every technology it can to understand infant brains, and what happens when development goes awry.
Seven centuries ago, tens of thousands of people fled their homes in the American Southwest. Archaeologists are trying to work out why.
News & Views
A modelling study argues that comprehensive policy change could limit Australia's environmental pollution while maintaining a materials-intensive path to economic growth. But other paths are worth considering. See Article p.49
What could cause a water droplet to start bouncing on a surface? It seems that a combination of evaporation and a highly water-repellent surface induces droplet bouncing when ambient pressure is reduced. See Letter p.82
Cutting-edge experiments show that the hormone leptin, which is secreted by fat cells, promotes fat loss by activating the release of catecholamine signalling molecules from neurons wrapped around the fat cells.
The discovery that potassium ion channels are involved in electrical signalling between bacterial cells may help to unravel the role of ion channels in microbial physiology and communication. See Article p.59
A sensitive cold-ion experiment probes sound at the level of phonons, the fundamental quantum units of vibration. It shows that phonons mix in such a way that they can be classified as 'bosonic' particles, like photons. See Letter p.74
Single-cell analyses reveal that combinatorial changes in the intracellular locations of transcription factors can tune the expression of the factors' target genes in response to environmental stimuli. See Article p.54
A multi-model framework that accounts for climate, water, energy, food, biodiversity and economic activity in Australia reveals that a sustainable society that enjoys economic improvement without ecological deterioration is possible, but that specific political and economic choices need to be made to achieve this.
Many gene-regulatory proteins have been shown to activate in pulses, but whether cells exploit the dynamic interaction between pulses of different regulatory proteins has remained unexplored; here single-cell videos show that yeast cells modulate the relative timing between the pulsatile transcription factors Msn2 and Mig1—a gene activator and a repressor, respectively—to control the expression of target genes in response to diverse environmental conditions.
Ion channels in bacterial biofilms are shown to conduct long-range electrical signals within the biofilm community through the propagation of potassium ions; as predicted by a simple mathematical model, potassium channel gating is shown to coordinate metabolic states between distant cells via electrical communication.
Piezo1, a mechanosensitive cation channel, senses shear stress of blood flow for proper blood vessel development, regulates red blood cell function and controls cell migration and differentiation; here a trimeric architecture of this novel class of ion channel is reported, suggesting that Piezo1 may use its peripheral propeller-like ‘blades’ as force sensors to gate the central ion-conducting pore.
A study of 12CO outflow emission from the protostellar source CARMA-7 in the cluster Serpens South suggests that episodic ejections of mass by the protostar begin in the earliest phase of protostellar evolution, probably providing a mechanism for driving the turbulence that is necessary for star formation in clusters.
The Hong–Ou–Mandel effect is a quantum phenomenon that involves the interference of bosonic particles and demonstrates their indistinguishability; this effect has been demonstrated previously for photons and neutral atoms, and is now demonstrated for phonons, using a system of trapped ions that are promising building blocks for quantum computers.
An affordable, safe, and scalable battery system is presented, which uses organic polymers as the charge-storage material in combination with inexpensive dialysis membranes and an aqueous sodium chloride solution as the electrolyte.
Spontaneous levitation and trampoline-like bouncing behaviour of water droplets on rigid superhydrophobic surfaces in a low-pressure environment are observed, and are due to a build-up of overpressure in the surface texture beneath the droplets.
Chemical methods for adding carbon-based or nitrogen-based functional groups to alkenes are well established, but strategies for adding both to the same double bond have limitations; here, a method for the carboamination of alkenes at the same double bond is described.
An analysis of 344 species of tetrapods (birds, mammals, reptiles and amphibians) shows that taxa in which the female is heterogametic tend to have a more male-biased sex ratio; the mechanisms driving the association are unclear, but sex-determination systems are likely to have important consequences for the social behaviour and demography of tetrapods.
A neuronal model of bipolar disorder based on induced pluripotent stem cell (iPSC) technology finds hyperactive action-potential firing and differential responsiveness to lithium in iPSC-derived neurons from patients with bipolar disorder.
Expression of the tumour suppressor PTEN in disseminated primary tumour cells is lost after tumour cells metastasize to the brain, with downregulation instigated by microRNAs from astrocytes, which are transferred from cell to cell by exosomes; these findings reveal the dynamic nature of metastatic cancer cells when adapting to a new tissue environment.
In response to cancer-associated stress, autophagy machinery mediates degradation of nuclear lamina components in mammals, suggesting that cells might degrade nuclear components to prevent tumorigenesis.
Cas9 is an RNA-guided DNA endonuclease that targets foreign DNA for destruction as part of a bacterial adaptive immune system mediated by clustered regularly interspaced short palindromic repeats (CRISPR). Together with single-guide RNAs, Cas9 also functions as a powerful genome engineering tool in plants and animals, and efforts are underway to increase the efficiency and specificity of DNA targeting for potential therapeutic applications. Studies of off-target effects have shown that DNA binding is far more promiscuous than DNA cleavage, yet the molecular cues that govern strand scission have not been elucidated. Here we show that the conformational state of the HNH nuclease domain directly controls DNA cleavage activity. Using intramolecular Förster resonance energy transfer experiments to detect relative orientations of the Cas9 catalytic domains when associated with on- and off-target DNA, we find that DNA cleavage efficiencies scale with the extent to which the HNH domain samples an activated conformation. We furthermore uncover a surprising mode of allosteric communication that ensures concerted firing of both Cas9 nuclease domains. Our results highlight a proofreading mechanism beyond initial protospacer adjacent motif (PAM) recognition and RNA–DNA base-pairing that serves as a final specificity checkpoint before DNA double-strand break formation.
The X-ray crystal structure of influenza C virus polymerase, captured in a closed, pre-activation confirmation, is solved at 3.9 Å resolution; comparison with previous RNA-bound structures reveals large conformational changes associated with RNA binding and activation, and illustrates the notable flexibility of the influenza virus RNA polymerase.
In DNA demethylation, human TET proteins are evolutionarily tuned to be less reactive towards 5hmC and facilitate its generation as a potentially stable mark for regulatory functions.